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<TITLE>80386 Programmer's Reference Manual -- Opcode POPA</TITLE>
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<B>up:</B> <A HREF="c17.htm">
Chapter 17 -- 80386 Instruction Set</A><BR>
<B>prev:</B><A HREF="POP.htm"> POP Pop a Word from the Stack</A><BR>
<B>next:</B><A HREF="POPF.htm"> 
POPF/POPFD Pop Stack into FLAGS or EFLAGS Register</A>
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<H1>POPA/POPAD -- Pop all General Registers</H1>

<PRE>
Opcode   Instruction   Clocks   Description

61       POPA          24       Pop DI, SI, BP, SP, BX, DX, CX, and AX
61       POPAD         24       Pop EDI, ESI, EBP, ESP, EDX, ECX, and EAX
</PRE>


<H2>Operation</H2>

<PRE>
IF OperandSize = 16 (* instruction = POPA *)
THEN
   DI := Pop();
   SI := Pop();
   BP := Pop();
   throwaway := Pop (); (* Skip SP *)
   BX := Pop();
   DX := Pop();
   CX := Pop();
   AX := Pop();
ELSE (* OperandSize = 32, instruction = POPAD *)
   EDI := Pop();
   ESI := Pop();
   EBP := Pop();
   throwaway := Pop (); (* Skip ESP *)
   EBX := Pop();
   EDX := Pop();
   ECX := Pop();
   EAX := Pop();
FI;
</PRE>

<H2>Description</H2>

POPA pops the eight 16-bit general registers. However, the SP value is
discarded instead of loaded into SP. POPA reverses a previous 
<A HREF="PUSHA.htm">PUSHA</A>,
restoring the general registers to their values before 
<A HREF="PUSHA.htm">PUSHA</A> was
executed. The first register popped is DI.
<P>
POPAD pops the eight 32-bit general registers. The ESP value is
discarded instead of loaded into ESP. POPAD reverses the previous
<A HREF="PUSHA.htm">PUSHAD</A>, 
restoring the general registers to their values before 
<A HREF="PUSHA.htm">PUSHAD</A>
was executed. The first register popped is EDI.

<H2>Flags Affected</H2>

None

<H2>Protected Mode Exceptions</H2>

#SS(0) if the starting or ending stack address is not within the stack
segment; #PF(fault-code) for a page fault

<H2>Real Address Mode Exceptions</H2>

Interrupt 13 if any part of the operand would lie outside of the effective
address space from 0 to 0FFFFH

<H2>Virtual 8086 Mode Exceptions</H2>

Same exceptions as in real-address mode; #PF(fault-code) for a page
fault


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<P>
<B>up:</B> <A HREF="c17.htm">
Chapter 17 -- 80386 Instruction Set</A><BR>
<B>prev:</B><A HREF="POP.htm"> POP Pop a Word from the Stack</A><BR>
<B>next:</B><A HREF="POPF.htm"> 
POPF/POPFD Pop Stack into FLAGS or EFLAGS Register</A>
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